Electric Power ›› 2023, Vol. 56 ›› Issue (1): 126-131.DOI: 10.11930/j.issn.1004-9649.202107126

• Power System • Previous Articles     Next Articles

A Voltage Balancing Control Strategy for Modular Multilevel Converter Based on Allowable Capacitance Voltage of Sub-modules

ZHANG Binqiao1, LI Cheng1, LI Zhenxing1, XIAO Bowen2, LIU Chuang2, WANG Fei2   

  1. 1. College of Electrical Engineering and New Energy, Three Gorges University, Yichang 443002, China;
    2. Jingmen Power Supply Company, State Grid Hubei Electric Power Co., Ltd., Jingmen 448000, China
  • Received:2021-08-02 Revised:2022-12-06 Accepted:2021-10-31 Online:2023-01-23 Published:2023-01-28
  • Supported by:
    This work is supported by the National Natural Science Foundation of China Youth Fund Project (No.52007102).

Abstract: Aiming at the problems of high switching frequency, large switching loss and large amount of computation in traditional voltage balancing strategy for modular multilevel converter (MMC), an improved capacitor voltage balancing control strategy is proposed. The sub-module (SM) voltage is constantly kept in the specified range through introducing the allowable value variable of capacitor voltage, consequently reducing the loss of power devices. In the meantime, all the sub-modules need not to be sorted in each control cycle, thus further reducing the amount of computation of the control strategy. Finally, the Matlab/Simulink-based simulation is carried out and the results show that the proposed strategy can significantly reduce the switching times of power devices per unit time.

Key words: modular multilevel converter, sub-module capacitor voltage balancing, switching frequency, allowable value